Certain medical conditions or diseases require that patients intermittently inject a drug or therapeutic agent subcutaneously to maintain the medical condition or disease under control. Multiple daily injections (MDIs) may be required. One such medical condition is diabetes, for which insulin is injected to regulate blood glucose. An estimated twenty-six million people in the United States, or about 8% of the population, have diabetes. This percentage is expected to increase in the near-term as the population ages.
Certain patients are unlikely or unable to follow the drug regimen required to maintain their medical condition under control. Some patients are squeamish about injecting the drug themselves and others suffer adverse effects from repeated injections, such as bruising at the injection site. To accommodate such patients, injection ports have been developed which only require that the patient puncture their skin every few days to install an injection port, rather than injecting with a needle into their skin numerous times a day. Injection ports employ a cannula inserted subcutaneously, and the patient injects the drug into the injection port adhering to their skin rather than directly into their cutaneous tissue.
A new problem arises with damage to the injection port itself. When the injection needle strikes the injection port's cannula, the cannula may be damaged so that the delivery of the drug is no longer controlled. The drug leaks from the damaged portion of the cannula before reaching the required subcutaneous depth. Although a shorter injection needle can be used to attempt to avoid such problems, such needles may not be locally available, limit flexibility in requiring a certain needle length, and provide no assurance that the patient may not still use a longer needle that damages the injection port.
It would be desirable to have a therapeutic agent injection device that would overcome the above disadvantages.